[CASSANDRA-18305] Enhance nodetool compactionstats with existing MBean metrics

• Type: Improvement
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 5.0-alpha1, 5.0
• Component/s: Tool/nodetool
• Change Category: Operability
• Complexity: Low Hanging Fruit
• Platform: All

Source Control Link

https://github.com/apache/cassandra/commit/7998e22127b7c612e26f56b5712639473d91576f

Test and Documentation Plan

NodeTool logs check

• Assignee: Manish Ghildiyal
• Reporter: Brad Schoening

Authors

Manish Ghildiyal, Stefan Miklosovic

Reviewers

Brandon Williams, Maxwell Guo, Stefan Miklosovic

• Created: 07/Mar/23 20:45
• Updated: 12/Jun/24 13:46
• Resolved: 23/Jun/23 09:20

Description

Nodetool compactionstats reports only on active compactions, if nothing is active, you see only:

$nodetool compactionstats

pending tasks: 0

but in the MBean Compaction/TotalCompactionsCompleted there are recent statistic in events/second for:

• Count
• FifteenMinueRate
• FiveMinueRate
• MeanRate
• OneMinuteRate

1) It would be useful to see in addition:

pending tasks: 0

compactions completed: 20

    1 minute rate:    0/second

   5 minute rate:    2.3/second

  15 minute rate:   4.6/second

2) Since compaction_throughput_mb_per_sec is a throttling parameter in cassandra.yaml (default 64 MBps), it would be nice to show the actual compaction throughput and be able to observe if you're close to the limit.  I.e., 

compaction throughput 13.2 MBps / 16 MBps (82.5%)

3) for completness, compactionstats should list the number of concurrent compactors configured, perhaps simply add to existing 'pending tasks' line:

4 concurrent compactors, 0 pending tasks

Issue Links

• incorporates: CASSANDRA-13890 Expose current compaction throughput
• links to: GitHub Pull Request #2333
• links to: GitHub Pull Request #2375
• links to: GitHub Pull Request #2393
• links to: GitHub Pull Request #2422
• links to: GitHub Pull Request #2432